A frame grab from a video released by the Taliban shows a man believed to be Bowe Bergdahl, left. / IntelCenter via AP

by Tom Vanden Brook and Jim Michaels, USA TODAY

by Tom Vanden Brook and Jim Michaels, USA TODAY

WASHINGTON - Army Sgt. Bowe Bergdahl, the military's only missing service member in Afghanistan, is alive although in declining health, according to a video obtained by the Pentagon.

Col. Steve Warren, a Pentagon spokesman, confirmed that the video shows Bergdahl, who was captured by the Taliban more than four years ago.

Bergdahl was 23 when he disappeared from his base in southeastern Afghanistan on June 30, 2009. Last June, the Taliban said it would free Bergdahl in exchange for five senior officials held by the United States at the prison in Guantanamo Bay, Cuba.

A second Pentagon official said the video is legitimate and shows Bergdahl in poor health. The video is thought to be about a month old. The military obtained the video in the last few days, said the official, who asked to speak anonymously because the information was not authorized to be released publicly.

Bergdahl's family provided a statement released by the Army: "Today we learned that a new video of our son, U.S. Army Sgt. Bowe Bergdahl, has been distributed by his captors.

"Naturally, this is very important to us and our resolve to continue our efforts to bring Bowe home as soon as possible.

"As we have done so many times over the past 4 and a half years, we request his captors to release him safely so that our only son can be reunited with his mother and father."

The military continues extensive efforts to find Bergdahl, including the an array of intelligence and surveillance equipment, the Pentagon official said.

Shortly after his capture, drones collected video images of soldiers engaged in nighttime searches for Bergdahl.

The prospects of talks last year revived hopes that Bergdahl might be released, and his family was "encouraged by the possibility of discussions," Marsano said last year.

"We cannot discuss all the details ... of our efforts, but there should be no doubt that on a daily basis - using our military, intelligence and diplomatic tools - we work to get Sgt. Bergdahl returned home safely," Pentagon spokesman Lt. Col. Jim Gregory said in a statement last year.